(Adapted from the applicant's abstract): The broad long-term objectives of this research are to validate a conceptual framework for studying and understanding factors influencing both the acute pain and stress response and long-term sequelae of painful medical procedures in multiethnic children. The specific aims are: 1) to validate psychometric instruments commonly used to measure pain and stress in ethnic minority children; 2) to investigate differences between children and parents of different ethnic groups in pain beliefs, pain coping skills, and parent-child interactions as related to the child's pain and stress response; 3) to validate post-traumatic stress disorder (PTSD) symptoms as a measure of the long-term effects of painful experiences; and 4) to test a pharmacological (intramuscular ketamine and midazolam) and a behavioral (blowing on a party blower) intervention for reducing the pain and stress response. Children aged seven to 14 years from three ethnic groups, Caucasian, African-American, and Mexican-American, undergoing painful medical procedures typically done with no or local anesthesia only (e.g., laceration repair, fracture reduction, incision and drainage of an abscess, lumbar puncture) will be studied. Patients will be recruited from the pediatric emergency department and pediatric clinics. Parents and children will be interviewed for demographic information, history regarding the current injury or illness, and the child's previous pain experiences, and surveyed using previously validated instruments regarding their pain coping skills and anxiety level. Children will report their pain intensity using a validated self-report scale before, during, and after the procedure. Children and surrounding adults will be videotaped, and a trained nurse will review the tapes and score a behavioral measurement of pain intensity, and a scale measuring the amount and type of interactions among the child and the parent and health care providers. Physiologic measurements of pain (heart rate, blood pressure, and salivary cortisol) will also be measured. Children will follow-up three days, one week, one month, and three months after the procedure, and will be assessed for PTSD symptoms and self- reported hypothetical pain response to pictures of painful medical situations and procedures. The second study will be performed as above with half of the patients within each ethnic stratification receiving intramuscular ketamine and midazolam, while the other half serves as a control group. The third study is similar with the intervention tested being behavioral (blowing on a party blower, for distraction) instead. Differences in pain beliefs, pain coping skills, and parent-child interactions between the three ethnic groups will be examined and correlated with any differences in the acute pain and stress response, and the long-term sequelae (PTSD symptoms). Elucidation of factors influencing children's pain response, and study of interventions to reduce pain, are important priorities for all clinicians who care for children.